Report 1 - Conservation of ceramic firepot
Report 2 - Composite wood and iron artifacts - pole arms and partisans
Report 3 - Silicone oil and organic conservation
Report 4 - Conserving the human skeleton found aboard La Belle
Report 5 - Conservation of closed wood containers: a chest from La Belle
Report 6 - Conservation of the Fairfield Union field cannon
Report 7 - Conserving the hull of La Belle
Report 8 - A carpenter's tool from Port Royal, Jamaica
Report 10 - Site 8SJ3478, possibly the Industry: a British 18th-century shipwreck
Report 11 - Pass Cavallo project (Page currently down)
Report 12 - A chest from the Brother Jonathan shipwreck.
Report 13 - Reconstructing historic mine cars
Report 14 - Conserving a dugout canoe
Report 15 - The Conservation of the 18-Pounder Carronades from USS Shark
Conservation Research Laboratory Reports
Composite wood / iron objects: pole arms and partisans
La Salle Shipwreck Project
Texas Historical Commission
CONSERVATION OF AN IRON BLADE
Radiographs (right) of encrusted metal artifacts, such as the partisan (below), can reveal where sound metal remains, as well as show areas of metal that have since corroded. It is sometimes difficult, however, to determine from the X rays if the corrosion products are solid or if they are merely loose slush. To find out, the conservator has no choice but to break open the encrustation. If all that remains is loose slush and a natural mold of the artifact, the mold can be easily cast in epoxy. If the corrosion products are solid, a different tactic must be used. |
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When the encrusted partisan (above) was broken in half, we realized that the corrosion products were, in fact, solid. Our original plan of casting the entire piece had to be slightly modified.
After the broken encrustation was fitted back together, it was pressed into a box containing plaster-of-Paris (below left). The plaster supported the back half of the encrusted piece, while the conservator slowly removed the encrusted top half. The conservator used an S.S. White Airbrasie unit to cut through the encrustation (below right). The precision of this tool ensured that the thin cutting edge of the partisan blade would not be inadvertently destroyed.
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After cutting off the top surface of the encrustation, all of the metal corrosion layers were removed. Special care was taken to clean the sharp edges of the blade. Hysol LE-6329 NA epoxy (no longer available) was poured into the open areas, making sure it flowed along the edges. The different pieces of the top encrustation were then placed on top of the epoxy, so that it would pick up the natural surface of the original blade surface.
Part epoxy/part metal partisan removed from the encrustation |
Silicone rubber mold made of part metal/part epoxy partisan |
Part metal/metal oxide and part expoxy partisan as removed from the encrustation after filling voids with epoxy |
Silicone rubber mold cast with Hysol LE 6329 NA epoxy |
After the epoxy set, the cast was removed and covered with a coating of graphite to give it a metallic appearance (right). There is additional work to be done on the metal straps that project from the partisan, connecting it to the shaft. |
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